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Trigonometric identities sheet

20 identities grouped the way you reach for them — Pythagorean, double angle, half angle, sum and difference, product to sum, and the reciprocal and quotient definitions — with the section breaks falling between groups rather than mid-run.

Trigonometric identities sheet

20 rows · CalcRef · sample of the first 6 rows

Pythagorean identities

Pythagorean identities
IdentityStatement
Pythagorean (sin/cos)sin⁡2θ+cos⁡2θ=1\sin^2\theta + \cos^2\theta = 1
Pythagorean (tan/sec)1+tan⁡2θ=sec⁡2θ1 + \tan^2\theta = \sec^2\theta
Pythagorean (cot/csc)1+cot⁡2θ=csc⁡2θ1 + \cot^2\theta = \csc^2\theta

Double-angle identities

Double-angle identities
IdentityStatement
Double Angle (sin)sin⁡2θ=2sin⁡θcos⁡θ\sin 2\theta = 2\sin\theta\cos\theta
Double Angle (cos) Icos⁡2θ=cos⁡2θ−sin⁡2θ\cos 2\theta = \cos^2\theta - \sin^2\theta
Double Angle (cos) IIcos⁡2θ=2cos⁡2θ−1\cos 2\theta = 2\cos^2\theta - 1

The 20 rows of the CalcRef trigonometric-identity reference table, grouped by the categories the dataset carries.

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